Railway signaling



March 22 1927 F. H. NICHOLSON RAILWAY S IGNALING Original Filed May 13, 1922 WAL. mm;

INVENTOR.

M1. ATTORNEY Patented Mar. ZZ, i927.

narran srArcs LZLXa MTENT trice,

FRANK I-I, NCHOLSON, OF EDGEWOOD BOROUGH, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH a SIGNAL COMPANY,

PORATON OF PENNSYLVANIA.

OF SWSSVALE, PENNSYLVANIA, A COR- RAILWAY SIGNALING.

Application filed May 13, 1922, Serial No. 560,568. Renewed December 2, 1926.

My invention relates to railway signaling, and particularly to signaling,` of the type wherein the signals are controlled by track circuits or other circuits containingl sources of current which are reversible as to polarity.

One object ot' my invention is the provision ot novel and improved means tor preventing' a. signal from momentarily giving a stop indication when the polarity of the current supplied to the associated controlling circuit is reversed.

l wil describe Several forms of railway signaling` systems embodying my invention and will then point out the novel features thereof in claims.

ln the accompanying drawings, Fig. 1 is a diagrammatic view showing one form Vof signaling; system embodying my invention, the systcn'i in the or'm here shown comprisinc' light signals. 2 is a view similar to Fig. 1 and also embodying` my invention, but showing; a system comprising semaphore signals. Fig. is view showing a modilication ot the light sional system shown in Fig. 1, and ig. Ll is a view showingl a modification ot the semaphore signal system .shown in Fig. 2, both also embodying my invention.

Similar reterence characters refer to similar parts in each of the several views.

Referring iirst to Fig. 1, the reference characters 3 and 3a designate the track rails et' a railway along which tratiic normally moves in the direction indicated by the ar-V row. These rails are divided by insulated joints to form artrack section A-B, which section is provided with a track circuit comprising' as usual a source of current and a track relay. secondary 51 of a transformer TB, the primary 51A ot which is connected with a transmission line F to which alternating signaling` current is constantly supplied by a generator El. Secondary 51 is connected with the rails of section A-B through th-e medium of a pole-changing device which is hereinafter explained. The relay for section Ai-B is designated by the reference character BA, and as here shown is of the polyphase motor type, comprising a rotor 4i, a stator winding 5 connected with'the track rails, and a. second stator winding 6 constantly supplied with signaling current from a secondary 11 on a transformer TA. The prirlhe source of current is the.

mary 32 of the latter transformer is connected with the transmission line F.

The track section B-C lying to the right ot section A-B is also provided with a track circuit comprising` the secondary 51 ot a transformer TC, and a relay DB which is similar to track relay DA. The contacts i9 and 50 of the relay DB constitute a polecl'ianger tor reversely connecting secondary 5l of transformer TB with the rails 01" section When relay DB is energized in either direction, the right-hand terminal ot secondary 51 is connected with the lower rail 8A and the lett-hand terminal is connected with the upper rail 3. The current which is thenk supplied to the rails of section A-B is of what I will term normal relative polarity. When relay DB is de-energized, however, the right-hand terminal of secondary 51 is connected with the upper rail 3 and the letthand terminal is connected with the lower rail 3A, so that current ot what l will term reverse relative polarity is then supplied to the section A-B.

Relay DA is responsive to reversals oi relau tive polarity oi the current supplied to the, track rails of its associated section. `When the current is of normal relative polarity, contact linger 7 is swung` to the right, whereas when the current is of reverse relative polarity this contact linger is swung to the left. When the track section A-B is occupied, relay lDA is, of course, de-energgized7 so that contact S is closed and contact finger 7 occupies a vertical or intermediate position.

Located adjacent the entrance end of section A-B is a signal SA, which, as here shown, is ot the light signal type,v comprising three lamps G, Y and R, indicating when illuminated, proceed, caution" and stop, respectively. rlhe proceed lamp ii is provided with a circuit which passes from the left-hand terminal of secondary ot transform-er TA, through wi es 12 and '13, right-hand point of contact 7, wire 14, lamp G, wires and 16 to secondary 10. This lamp is illuminated, therefore, only when relay DA is energized in normal direction. The caution lamp Y is provided with a circuit which passes from the lettehand` terminal of secondary 10, through wires 12 and 13, lett-hand point of Contact 7, wire 17, lamp Y and wires 15 and 16 to secondary 10. It

follows that this lamp is illuminated only when relay DA is energized in' reverse direction. The stop lamp R is controlled hy a thermo-sensitive cell E comprising a'heating elehi'ent and a thermo-sensitive element 2li' The heating elen'ien-t 19 is provided with a circuit which passes from secondary 10, through wires 12 and 18, contact 8, heating clement 19, and wires 2O and 16 to secondary 10. This circuit is, of course', closed only when contact 8 is closed, that is,when relay DA istie-energized; The circuit for the stop lamp R is from secondary 10, through wires 12 and'18, contact 8, heating element and thermo-sensitive element of cell E, wire 52, lamp Rand wires 15 and 16 to secondary 10. The thermo-sensitive cell E has a negative temperature coefficient; that is, the resistance ot the element 21.?dccreases with increase'oi temperature. The partsare so adjusted that lamp Rfis supplied with sufficient current to lig-ht this'lamp only when cell E is hot; that is, Vonly when-current has been supplied for a certain length of time to heating element 19; lVhenthe cell is cold and contact 8 is closed a certain period of time will, of course, elapse Vloeiore the thermo-sensitive element 21 is hea-ted to such temperature as to permit sufficient current' to. pass therethrough to light the lamp R. This time element is utilized in a manner which will appear hereinafter.

AThe operation oit' the apparatus shown in liig.v 1 is as follows:

When both sections A'-B and B-C are unoccupied, as shown in the drawing, relay-DB is, of course, energized, so that current of normal relative polarity is supplied to therailsk of section A-B. Relay DA is, therefore, energized in normal direction, so that lamp Gr is lighted and the signal SA consequently indicates proceed. Then a car or train moving toward the right entersgsection A-B, its wheels and axles will shunt the track `circuit current -from winding 5 of' relay DA, so that this relay will hecomede-energized. The opening of con tact 7 will extinguish the proceed lamp G andthe closing of contact 8 will cause the stop lamp R to'become lighted. As the train passes from section A-B into section BQC, it will cle-energize relay DB, so that current of reverse polarity will Vhe supplied to the rails of .section A--B Relay DA will,k

therefore, become energized `in .reverse direction,- so that the stopA lamp R will become extinguished and the caution lamp Y will become lighted. As th'et-rain passes out of section B--C, relay DB will become energized, so that the polarity of the current supplied -tosection A-B will he reversed. During this,reversalfcontact of relay D A will momentarily', close, thereby completing the circuiti for the heating 'element 139 of the thermo-sensitive cell E. The length of time during which contact 8 is closed, however, is very short, and is n'ot'sutiici'ent to permit the temperature of element 2l to loe raised to such point that enough current is supplie-d to lamp R to light this lamp.` The result is that lamp R remains extinguished during the reversal ot' relay DA. This reversal closes the circuit for the proceed lan'rp Gr so that the parts of the apparatus are then restored to the conditions in which they are shown in the drawing.

Referring now to Fig. 2, the apparat-us shown herein is simila-rto that illustrated in Fig. 1, except that a semaphore signal SAl is substituted for the light signal SA of Fig. 1. Section B-C is provided with a similar signal SR1, which in Lturn operates a'V polechanger P for controlling the relative polarity of the current supplied to the rails of section hytransformer TB.

The signal SAl is provide-d withl a caution indication circuit and with a proceed indication circuit. The caution circuit is controlled hy al thermo-sensitive cell E, comprising aheating element 19, a thermo-sensitive element 29, and anV electrode 30. The heatingv element 19-is provided with a circuit which passes from the left-hand terminal otsecondary 10, through wiresV 21', 22 and 26, contact 8 of relay DA, wire' 27 or 28, heating element 19, and wire 16 to secondary 10. This circuit is closed only when' relay DA is energized in either direction, but open w'hen the relay is cle-energized. The caution indication circuit for signal SAl passes from secondary 10, through wires 21 and 54, thermo-sensitive element 29 and electrode 30 of cell E, wire 31, operating mechanism ot signal SA1, and wires 25 and 16 to secondaryilO. The parts of this circuit are so proportioned that-suiiicient current is supplied to the signal mechanism to actuate this signal only when the thermosensitive cell E is heated. The proceed indication circuit is from the secondary 10, through wires 21, 22 and 23, contact 7, wire 24, operating mechanism of signal SAl, and wires 25 and 16 to secondary 10. This circuit is, of course, closed only when relay DA is energized in normal direction.

The operation of the apparatus shown in Fig. 2, is asl follows:

lVhen hothtrack sections A -B :fnd B--G are unoccupied, as shown in the drawing, relay DA'is energized in normal direction, so that signal SAl indicates proceed.` Then a car or train moving toward the right en ters section A-lit -de-energizes relayY DA, so that the proceed indication circuit for sigal SAl is opened at contact i of this relay. At the same time the circuit for the heating element 19 is openedat contact 8, and after ajshort interval of time, suiiicient to permit the cell E to cool down, the conductivity of this'cell is reduced to suchvalue that, ineffect, the caution indication circuit for the signal SA,L is open. This signal consequently moves to the stop position. As the train leaves section A--B and passes into section B-C, it places signal SB1 in the stop position, and this signal in turn reverses polecnanger P so that current of revers-e polarity is supplied to the rails of section ,4l-P Contacts 7 and 8 of relay DA are then swung to the left, so that the heating element 19 of the thermo-sensitive cell E becomes energized. After a short interval of time the temperaturel of this cell is raised to such value that the caution indication circuit for signal SA1 becomes energized, whereupon this signal moves to the caution position. When the train leaves section B C, signal SB1 moves to the caution position and .in doing so it restores the pole-changer lJ to its original position so that current of normal relative polarity is again supplied to the 'ails of section A-B- This reversal of polarity causes the contacts of relay DA to swing to the right, during which movement contact 8 is momentarily opened. The interval of time during which this contact is open, howevenis so short that the temperature o f the cell E is not materially reduced and so the supply of current to the caution indication circuit for signal SA1 is not interrupted. It follows that the signal is not released from the caution position. Contact 7 1s nowV closed, so that signal S1 moves to the proceed position.

It Will be observed from the foregoing that by virtue of the cell E the signal SA, is prevented from momentarily moving to the stop position during the reversal of relative polarity of the current supplied to the rails of section Ar-B.

Referring now to Fig. 3, the apparatus shown therein is the same as that shown in Fig. 1, except as to the means for controlling the supply of current to the stop lamp R of signal SA. In F ig. 3 the circuit forrlainp R includes an electron tube J, comprising a filament 36 and a plate l1. The lament 36 is provided with an energizing circuit which passes from secondary 33 of transformer TA, through Wire 34, contact 9 of relay DA, Wires 35 and 12, lament 36 and Wire 37 to secondary 33. Contact 9 is closed only when relay DA is de-energized. The circuit for the stop lamp R is from secondary 38 to transformer TA, through Wire 39, contact 8 of relay DA, Wire 4:0, plate and filament of tube J, Wires l2 and 43, lamp R and wire 414 to secondary 38. The electrical conductivity of the tube J is relatively low when the filament 36 is de-energized, and relatively high when the filament is heated by energization, and so it Will be seen that current of suficient value to light the lamp R is furnished to this lamp only when filament 36 is energized. Furthermore, when lilament 36 becomes energized, a certain interval of time Will elapse before its temperature Will be raised to high conductivity value so that the lighting of the lamp R will be delayed for a short interval of time after contact 9 is closed.

In the operation of the apparatus shown in Fig. 3 it Will, of course, be observed that when section B-.C is occupied signal SA indicates caution. passes out of section B-C the reversal of elative polarity of the curr-ent supplied to section A-B will cause contacts 3 and 9 of relay DA to close momentarily. The

momentary encrgization of filament 36 is not sufficient, however, to raise its temperature to the high conductivity value and so the stop lamp R is not lighted during this momentary closing of contacts 8 and 9.

Referring new to F 4, thermo-sensitive cell E is similar to the corresponding cell in Fig. il, but vthe heatingelement 19 of this cell is connected directly across the track rails 3 and 3A of section ril-B. The caution indication circuit' for signal SA, is

from secondary 10, through Wires i5 and 53,

thermo-sensitive cell l, operating mechanism of signal SA1 and Wire 13 to secondary 10. This circuit carries suiiicient current to operate the signal when heating element 19 is energized, but not when the heating element is de-energized. The proceed indication circuit for this signal. is from secondary 10, through Wires 115 and 4:6, normal contact 7 of relay DA, Wire 4f?, operating mechanism of signal SA1 and wire 418 to secondary l0.

The operation of the apparatus Vshown in Fig. e is as follows:

W'hen sections AMB and B-C are both unoccupied, signal SA1 indicates proceed, because the thermo-sensitive cell E is heated by the track circuit current and the proceed indication circuit is closed at Contact 7. Vvlhen a car or train moving toward the right enters section A-B, relay DA becomes cle-energized and the supply of current to the heating element 19 of the cell E isalso discontinued. The resistance of cell E is ytherefore increased, so that the caution indication circuit is in effect open at this point, and the proceed indication circuit for secondary SA1 is opened at Contact 7, so that this signal moves to the stop position. Vhcn the train enters section B-(l, current of reverse relative polarity is supplied to section ift-JB, so that relay DA becomes energized in the reverse direction wherein con tact 7 is open. Current is new supplied, however, to the heating element 19 of the cell E from the track circuit for section A--B, so that the caution indication circuit for signal SAl becomes conductive and so this signal moves to the caution position. As the train passes out of section B-C,

lWhen the car or train pole `changer P reverses, thereby supplying current of normal relativepolarity toY section lli-B, whereupon relay DA becomes energized in normal direction. The closing ot Contact 7 closes the proceed indication circuit for signal SAl so that this sig-nal moves to the proceedv position. During the. reversal of polarity of the track circuit current, the treating element 19 is momentarily de-energized, but not itor a period of time suicientto permit cell E to cool, and so the conductivity of the caution indication circuit is not materially reduced. It follows therefore that signal SA, is not released from the caution position during the reversal ot relative polarityof the track circuit current supplied to section rit-B.

Although I have herein shown and described only tour 'forms of signaling systems embodying. my invention, it is understood that various changes and modilications may be made therein Within the scope of the appended claims Without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

l. In combination, a relay capable of energization in opposite directions, a normal contact closedwhen the relay is energized in one direction, a reverse contact closed when the relay is energized in the other direction, a third contact closed wheny the relay is dei-energized and also closed momentarily when the direction of energization of the relay is reversed, signaling means controlled by said normal and reverse contacts, a thermo-sensitive cell having a heating element and a thermo-sensitive element, a circuit for said heating element controlled by said third relay contact, and signaling means controlled by the thermo-sensitive element of said cell.

Q. In combination, a relay capable oli energization in opposite directions, a normal contact closed When the relay is energized in one direction, a reverse contact closed when the relay is energized in the other direction, a third Contact closed When the relay is deenergized and also closed momentarily When the direction of energization of the relay is reversed, a thermo-sensitive cell having a heating element and a thermo-sensitive element, a circuit for said heating element controlled by said third relay contact, and signaling means controlled by said normal and reverse relay contacts and by said thermosensitive element.

In combination, a relay capable oi energization in opposite directions, a normal Contact closed When the relay is energized inone direction, a reverse' contact closed when the relay is energizedV inthe other direction, a third contactclosed when the relay is de-eneigized and-also closed momentarily when the direction of energization'of the relay is reversed, afthermo-sensitive cell controlled byV said thirdV relay contact, and signaling means controlledl by said normal and reverse relay contacts and by said thermo-sensitive cell.

4. In combination, a relay capable of energization in opposite directions, a normal Contact closed when the relay is energized in one direction, a reverse contact closed When the relay is energized in the other direct-ion a. third Contact closed When the relay is deenergized and also closed momentarily when the direction of energization of the relay is reversed, a thern'io-sensitive cell controlled by said third relay Contact; and a light signal having a proceed lamp controlled by said normal contact, va. caution lamp controlled by said reverse Contact and a stop lamp controlled by said thermo-sensitive ccll,

In combination, a relay capable of energization in opposite directions and having a contact which is closed when the relay is deenergized and also closed momentarily When the direction of energization ofthe relay is reversed, a thermo-sensitive cell having a heating element and a thermo-sensitive element, means for controlling said heating element by said relay contact, and signaling means controlled by the thermo-sensitive element or' said cell.

6. In combination, a relay capable of energization in opposite directions and having a Contact which is closed when the relay is deenergized and also closed momentarily When the direction of energization of the relay is reversed, a thermo-sensitive cell controlled by said relay contact, and signaling means controlled by said cell.

7. In combination, a relay capable oit energization in opposite directions and having a contact which is closed when the relay is deenergized and is also closed momentarily when the direction of energization of the relay is reversed, a substance having the characteristic of decreasing in electrical resistance with increase o1E temperature, a circuit including said substance and a signaling device, and means controlled by said relay contact for heating said substance.

8. In combination, a relay capable of energization in opposite directions and having a contact which is closed when the relay is deenergized and is also closed momentarily when the direction of energization of the relay is reversed, a heating element, means controlled by said relay Contact for energizing said heating element', and signaling means controlled by said' heatingelement.

i). In combination, a relay capable of energization in opposite directions and having a contact which isrclosed when the relay is deenergized and is also closed momentarily v-.fhen the direction of` energizationoffthe relay is reversed, a heating element, means .lili

lill? controlled by said relay contact for energizing said heating element, a circuit controlled by said heating element and substantially conductive or substantially nonconductive according as said element is energized or cle-energized, and signaling means controlled by said circuit.

10. In combination, a relay capable of en`- ergization in opposite directions, a signal controlled by said relay to indicate proceed, caution or stop according as the relay is energized in normal or reverse direction or is de-energizcd, and means including a thern'io-sensitive cell for preventing said signal from momentarily indicating stop when the direction of energization ot said relay is reversed. Y

11. ln combination, a relay capable of energization in opposite directions, a signal controlled by said delay to indicate proceed, caution or stop according as the relay is energized in normal or reverse direction or is ele-energized, and means including a heating element controlled by said relay for preventing said signal from momentarily indicatinc stop when the direction of energiza-- tion of said relay is reversed.

12. In combination, a track circuit coniprising track rails and a source ot current reversibly connected therewith; a signal controlled by said track circuit and arranged to indicate proceed when the track circuit is energized in one. direction, caution when the track circuit is energized in the other direction, and stop when the track circuit is occupied; and means including a thermo-sensitive relay controlled by said track circuit for preventing said signal from momentarily indicating` stop when the polarity ot the current supplied to the track circuit is reversed.

13. In combination, a track circuit comprising track rails and a source. ot current reversibly connected therewith; a signal controlled by said track circuit and arranged to indicate proceed when the track circuit is energized in one direction, caution when the track circuit is energized in the other direction, and stop when the track circuit is occupied; and means including a heating element controlled by said track circuit 'tor preventing said signal from momentarily indicating stop when the polarity of the current supplied to the track circuit is reversed.

14. In combination, a relay capable ot' energization in opposite directions, and having a contactwhich 1s closed when the relay is cle-energized and is also closed momentarily when the direction otA energization of the relay is reversed, a signal comprising a lamp controlled by said contact, and means included in the circuit of said lamp for delaying` the lighting of the lamp to full brilliancy, whereby said lamp does not flash during reversal oit said relay.

15. ln combination, a relay capable of energization in opposite directions, a normal contact closed when the relay is energized in one direction, a reverse contact closed when the relay is energized in the other direction, a third contact closed when the relay is deenergized and also closed momentarily when the direction of energization of the relay is reversed, a light signal comprising proceed, caution and stop lamps controlled respectively by the normal reverse and third contacts of' said relay, and means included in circuit with said stop lamp for delaying the lighting of the lamp to ull brillianc, whereby said lamp does not flash during reversal 01"? said relay.

16. In combination, a relay capable ot' energization in opposite directions, and having a contact which is closed when the relay is cle-energized and is also closed momentarily when the directin of energiza tion of the relay is reversed, a signal comprising a lamp controlled by said contact, and an element having resistance included in the circuit ol vsaid lamp for delaying the lighting of the lamp to full brilliancy whereby said lamp does not flash during Vreversal of said relay.

17. ln combination, a relay capable of energization in opposite directions, a normal contact closed when the relay is energized in one direction, a reverse contact closed when the relay is energized in the other direction, a third contact closed when the relay is cle-energized and also closed momentarily when the direction of energization of the relay is reversed, a light signal comprising proceed, caution and stop lamps controlled respectively by the normal, reverse and third contacts of said relay, and an im pedance included in circuit with said stop lamp tor delaying the lighting of the lamp to itull brilliancy, whereby the said lamp does not flash during reversal of said relay.

18. An electric circuit comprising an electric lamp, and means associated with said circuitand operating when the circuit is closed momentarily to prevent the flow ot sufficient current to said lamp to light the lamp.

19. A railway signal comprising an electric lamp, a circuit for said lamp including a source of energy, and means associated with said circuit and operating when the circuit is Vclosed momentarily to prevent the flow of sucient current to said lamp to light the lamp.

ln testimony whereof I ali'ix my signature.

FRANK H. NICHOLSON. 

